For decades, magnetic tape was the preferred format for data backup. Tape was comparatively cheap, easy to store, and held a lot of data.
Costly and unreliable. However, there are downsides to tape: newer tape media such as high-capacity DLT cartridges can run upwards of $50 or $75 each. A minimal tape rotation with two weeks' worth of daily backups plus one year of monthly backups requires a minimum of 24 tapes. Tape systems are still largely mechanical beasties requiring manual handling. Even tape libraries need to have tapes imported and exported on a regular basis. The only value a tape library adds over a standalone tape drive is to reduce the frequency of having to change out the tape media.
Take it away, bring it back. Then there's the headache and cost of paying a third-party service to take your backup tapes offsite and bring back your old backup tape for recycling or data restore. All of this adds up to a bunch of hidden costs of using tape.
eVault was the first all-electronic backup/recovery service that I recall running across. I was a bit doubtful at the time because in an emergency requiring a full server restore, one would need to have a tape cut and couriered from eVault to your local site for restoration. Also, internet bandwidth was comparatively slow, and the backups took a lot of time.
The state of e-backup today. Fast forward to today, and eVault has been joined by a number of companies such as Barracuda and WD Arkeia, all offering sophisticated backup appliances. Paired with a speedy internet connection--which has become a fundamental business requirement, rather than the luxury it was considered only ten years ago--these systems provide all of the functionality of a traditional tape backup system without any of the drawbacks.
All of the contemporary backup services my clients use these days back up to a locally installed appliance. The appliance, in turn, streams the backed-up data up to cloud storage. This eliminates the need to handle, courier, and/or store media offsite.
Extra value for virtualized shops. Some backup services log into machines using Administrator or root credentials to perform file-level backups. Others utilize backup agents. Still others back up entire virtual machines on hypervisors by leveraging APIs in VMware or Hyper-V. Many of the first-tier backup systems can also perform bare metal restores. Barracuda's system even allows you spin up a backed-up VM on their appliance temporarily if your primary storage fails...meaning recovery from a total systems crash is measured in hours, not days.
All of these systems are far easier and faster to set up than traditional backup/restore suites. Barracuda set the standard for ease of use: connect their appliance to the network, power it up, log into Barracuda's cloud and establish a web portal account, and link it to the appliance. That's as complicated as system setup ever gets.
Software licensing for such systems is very different from the "one server, one backup agent license" model. In Barracuda's business model, there's a one-time purchase of the appliance, and then fixed monthly or yearly charges for support, updates, and cloud storage. There are no per-server charges. Back up one server or back up a thousand; they license their backup by total capacity, not individual system.
There is a tradeoff. Cloud-based backup systems aren't quite as granular (yet) for backup scheduling as traditional systems such as Backup Exec or Arcserve. On the other hand, scheduling and backup granularity was needed by tape-based systems because multiple copies of each backed-up file were needed on multiple media. With cloud-based backup, that requirement falls away. Cloud-based backup systems rely heavily on compression and deduplication, storing a master copy of each file (or image), plus all subsequent changes.
Overall, installing cloud-based backup systems has allowed our company's engineers to relax and refocus from constantly tending backup systems to more productive tasks such as virtualization, proactive systems management, documentation, and training. All of our customers running cloud-based backup adore it. I've yet to see a single cloud-based backup system placed on trial with a customer come back in the door.